Fluorescence and brightfield microscopes have become indispensable tools for science and medicine. Traditional laboratory microscopes with photo capabilities needed for research and medical diagnostics are large, cumbersome, fragile, and expensive to the extent that they are priced out of reach for many potential users, including science teachers. Accordingly, many researchers, clinicians, and educators lack access to microscopes for their work. Furthermore, many microscopes are complicated to use and maintain, which hinders their use in many applications.
Schools struggle with modern conventional microscopes. They are foreign and intimidating to many students. Their complicated operation results in frequent difficulties such as misalignment, inappropriate interocular distances, incorrect condenser focus, and damaged or dirty objective lenses, in some cases due to the physical inaccessibility of these parts to the user. In many classrooms, the number of students easily exceeds the ability of a teacher to assist and verify what the students are or are not seeing. Because of these difficulties, teachers have resorted to using sophisticated microscope simulations since microscopy is such an important component of the modern curriculum (http://virtualurchin.stanford.edu/microtutorial.htm).
Many modern disease diagnostic assays utilize fluorescence, whether intrinsic to the sample, provided by the binding of a fluorescent molecule or an antibody labeled with a fluorescent moiety specific to a disease epitope, indirect immunofluorescence, or in situ hybridization of a fluorescently labeled nucleic acid sequence to a genetic marker of disease, among other diagnostic approaches. These diagnostic assays are limited in their availability to parts of the world where the deleterious impact of these diseases is greatest, due in part to the operational complexity and expense of fluorescence microscopes. Malaria infects an estimated 225 million people worldwide, yet many more cases may remain undiagnosed. During its lifecycle, the parasite dwells within the confines of red blood cells where it can be observed in a blood smear with suitable contrast enhancement or, because red cells contain no chromosomes, with a simple membrane-permeant fluorescent dye that intercalates and stains DNA. Yet due to the expense and cumbersome nature of modern fluorescence microscopes, these simple diagnostic tests are not being performed at locations where they are needed.
We describe a highly economical and compact inverted fluorescence microscope system, incorporating a brightfield and oblique transmission imaging mode and having a simple, yet robust design, with broad applications in research, science education, and point-of-care medicine to address these unmet needs.